U.S. Pat. No. 4,197,737, issued Apr. 15, 1980, to the present inventor, is related to a sensing device for sensing such parameters as the magnetic field, electric field, gas flow, linear acceleration and angular acceleration. The patented device is particularly directed to aircraft. Briefly, the patented device included a number of individual sensing units mounted for rotation on a common shaft, and commutator means are connected to enable coupling of the sensed voltage from the sensing device. The individual units are adapted to produce alternating voltage signals, the instantaneous maximum amplitudes of the signals corresponding generally to the vector of the measured physical characteristic in a given plane, such as a plane normal to the axis of rotation. As a consequence, substantially complete data regarding the physical characteristics may be provided by employing the sensing units.
Angular velocity about axes normal to the shaft are detected by a pair of crystals extending radially from the shaft and having bending axes normal to the shaft. With respect to the prior art device, it has been found that linear acceleration produces unwanted effects on the angular velocity pick-up unit. One approach to rid output signals from these unwanted effects required a number of slip rings and isolation amplifiers to bring signals to signal conditioners for mixing. In addition, it was previously necessary to provide a two-phase pickoff array to properly sense linear acceleration. Accordingly, it has previously been necessary to provide compensation for linear acceleration at a system level which becomes costly and adds a reliability factor to the unit.